A touch device has an advantage of easy operation. Recently, the touch device has been widely applied to various electronic products, for example, mobile telephones, personal digital assistants (PDAs), digital cameras, music players, computers, satellite navigation devices, touch screens, and so on. Generally, a familiar type of the touch device is, for example, a resistive touch device, a capacitive touch device or an optical touch device. The optical touch device has been paid attention to because the optical touch device has a durable property and a lower cost comparative to the resistive touch device or the capacitive touch device.
The optical touch device has a sensing region. It is necessary to provide light to the sensing region so that a sensing component can sense a position of a touch point in the sensing region. Typically, a light reflecting bar or a light guide bar is used for guiding a light beam from a light emitting component to the sensing region.
FIG. 1 is a partial, cross-sectional, schematic view of a conventional optical touch device using the light reflecting bar. Referring to FIG. 1, in an optical device 100, a light reflecting bar 130 is fixed to a plastic bar 140 via a double faced adhesive 150a, and the plastic bar 140 is fixed to a frame 110 via a double faced adhesive 150b and is fixed to a substrate 135 via a double faced adhesive 150c. The light reflecting bar 130 has a surface facing to a sensing region 102. A filter coating 120 is formed on the surface facing to the sensing region 102. For example, an infrared light can pass through the filter coating 120 while other light other than the infrared light can be filtered out by the filter coating 120.
Typically, in order to increasing a reflective efficiency of the light reflecting bar 130, a hot melt cutting process is applied to the light reflecting bar 130 and the filter coating 120. However, the hot melt cutting process is complicated, thereby causing a high production cost of the optical touch device 100. In addition, when the light reflecting bar 130 is fixed to the plastic bar 140 via the double faced adhesive 150a, it is difficult to exactly control an adhering position of the light reflecting bar 130. Thus, it is necessary to rework many times till the light reflecting bar 130 is exactly fixed to the plastic bar 140, thereby reducing a production yield of the optical touch device 100.